MDBT42Q-AT-UART-S is designed for testing and debugging without building your own board.
The board is only available with MDBT42Q-AT(Chip Antenna) module which pre-programmed with Raytac's AT command Peripheral/Slave Role firmware.

If you are looking for demo board for Central/Master Role AT command, please view MDBT42Q-AT-UART-M.
If you are looking for demo board for standard module WITHOUT AT command, please view MDBT42Q-DB for more information.